JP2023095163A - Lens support structure and optical ranging sensor - Google Patents

Abstract

To provide a lens support structure in which application balance of adhesive is stabilized and which suppresses deviation of an optical axis even against vibration or impact from the outside.SOLUTION: A lens support structure comprises a lens, a frame body holding the lens, and a base member supporting the frame body. The frame body has a pair of arm units extending in a direction not in parallel to an optical axis of the lens to be held and a projection unit provided in such a manner that it projects from a distal end of the arm unit to a side of the base member. The base member includes a flat portion and a raised portion that is raised from the flat portion to a side of the projection unit and comprises in an upper surface portion thereof, a recess for storing adhesive. The frame body is supported by the base member by inserting a distal end portion of the projection unit of the frame body into the recess of the raised portion and being surrounded by the adhesive.SELECTED DRAWING: Figure 5

Description

The present invention relates to lens support structures and optical ranging sensors.

A lens is three-dimensionally adjusted and incorporated into an optical distance measuring sensor or the like. A lens holder that holds a lens is often fixed to a base frame with an adhesive (see Patent Document 1, for example).

JP 2021-144158 A

When the adhesive drips in the direction of gravity or spreads out in the direction of the adhesive surface and hardens, the application balance to the lens holder may be lost. Such an unevenly cured adhesive causes deviation of the optical axis of the lens when it expands or contracts due to temperature changes in the environment in which the lens is used. If such a lens is incorporated in, for example, an optical distance measuring sensor, it will cause an output error.

The present invention has been made to solve such problems, and provides a lens support structure that stabilizes the adhesive application balance and suppresses the optical axis shift against external vibrations and impacts. and an optical distance measuring sensor employing the same.

A lens support structure according to a first aspect of the present invention includes a lens, a frame that holds the lens, and a base member that supports the frame. and a projection projecting from the tip of the arm toward the base member. and a protuberant portion provided with a depression for storing an adhesive on the upper surface thereof, and the tip of the protruding portion of the frame is inserted into the depression of the protuberance and surrounded by the adhesive so that the frame is a base member. supported by According to such a lens support structure, since the adhesive is stored in the recesses of the protuberances, it does not drip or spread during adhesion, and the frame holding the lens can be supported in a well-balanced manner. Further, since the recess is provided on the upper surface of the protruding portion protruded from the base member, the length of the protruding portion can be reduced. Therefore, even if the base member receives vibration or impact after being fixed, resonance of the frame can be suppressed, and the lens optical axis can be stably maintained.

Further, in the above lens support structure, the upper surface portion may be positioned above the lower end of the lens held by the frame. By arranging it in this way, in addition to being able to effectively suppress the vibration of the frame, it is expected to improve the workability of the operator's work of pouring adhesive into the recess and irradiating the adhesive with ultraviolet rays. can.

Further, in the above-described lens support structure, a groove may be provided in a part of the wall forming the recess to allow the adhesive overflowing from the recess to flow out. If such a guide groove is provided, even if a large amount of adhesive has flowed in by the operator, the excess adhesive can be released in a specific direction, thereby avoiding adverse effects on lens support. can.

Further, in the above lens support structure, the parallel length of the protrusion parallel to the optical axis direction of the lens may be longer than the length of protrusion from the arm toward the base member. If the arms extend in a direction orthogonal to the optical axis of the lens, for example, vibrations and shocks tend to tilt the surface of the lens. If it is formed to be relatively long, it will be strong against surface tilt.

Further, in the lens support structure described above, a through hole may be provided at the boundary between the arm and the projecting portion. Especially when the arms and protruding parts are formed long in the optical axis direction, the UV light from the UV irradiator that cures the adhesive is largely blocked by these members. allows more UV light to reach the adhesive.

In the above lens support structure, the adhesive includes at least an ultraviolet curable adhesive, and is surface-treated so that the ultraviolet reflectance of the surface of the recess is higher than the ultraviolet reflectance of the surface of the flat portion. may In order to prevent the reflection of stray light in the lens support structure, the surface of each member is usually light-shielded. Since it contributes to the hardening of the agent, it is preferable that the surface treatment is performed in this way.

The optical distance measuring sensor according to the second aspect of the present invention includes the above-mentioned lens support structure, a light projecting lens arranged between the light emitting element and the light projecting window, and between the light receiving window and the light receiving sensor. It is employed as a structure that supports at least one of the arranged light receiving lenses. Optical ranging sensors are often used in environments where the ambient temperature changes drastically, or in environments where they are frequently subjected to large vibrations and shocks. However, even when used in such an environment, an optical distance measuring sensor that employs the lens support structure described above can stably maintain the lens optical axis and output accurate detection results. .

According to the present invention, it is possible to provide a lens support structure that stabilizes the application balance of the adhesive and suppresses the deviation of the optical axis against external vibrations and impacts, and an optical distance measuring sensor employing the same. can.

It is a perspective view which shows the use condition of the ranging sensor in this embodiment. FIG. 4 is a perspective view showing the arrangement of the main components fixed to the base frame; 4 is a perspective view of the base frame; FIG. FIG. 4 is a perspective view of a light-receiving lens holder that holds a light-receiving lens; FIG. 4 is a cross-sectional view showing a light-receiving lens holder supported by a base frame; 4 is a perspective view of a projection lens holder that holds the projection lens; FIG.

Embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that, in each figure, the same reference numerals have the same or similar configurations. In addition, in each figure, when there are multiple structures having the same or similar configuration, in order to avoid complication, some are given the same reference numerals and the same reference numerals are omitted. There is

FIG. 1 is a perspective view showing a usage state of a distance measuring sensor 100 according to this embodiment. A distance measurement sensor 100 according to the present embodiment is an example of an optical distance measurement sensor, and is installed and used in a manufacturing line of a factory, for example. The distance measuring sensor 100 projects the detection light L1 emitted by the light emitting element toward the workpiece W, which is the object to be detected, through the light projection window 113 . Then, the detection light L2 reflected and returned by the work W is received by the light receiving sensor through the light receiving window 114, and the distance to the work W is measured from the light receiving position.

Inside the housing 111, in addition to the light emitting element and the light receiving sensor, a light projecting lens for projecting the detection light L1 to the workpiece W, a light receiving lens for guiding the detection light L2 to the light receiving sensor, and a CPU are included. A control board and the like on which a processing circuit is mounted are accommodated. A detection signal photoelectrically converted by the light receiving sensor is transmitted to the amplifier unit via the cable 112 . The amplifier unit converts the received detection signal into a numerical value and displays it on the display unit, or outputs it to a PLC or PC which is an external device. Note that the distance measuring sensor 100 may incorporate the function of an amplifier unit. In that case, the housing 111 includes a display unit for displaying numerical values and a communication unit for communicating with external devices. Also, the x-, y-, and z-axes are defined as shown. In subsequent drawings, the same coordinate axes as in FIG. 1 are used to indicate the direction of the structure represented by each drawing.

FIG. 2 is a perspective view showing the arrangement of major components fixed to the base frame 120. As shown in FIG. The base frame 120 is a base member that supports at least the light-receiving lens holder 140 that holds the light-receiving lens 130 , the light-projecting lens holder 160 that holds the light-projecting lens 150 , the reflecting mirror 170 , the light-receiving sensor 180 , and the light-emitting element 190 . It should be noted that depending on the configuration of the distance measuring sensor, there may be a sensor that does not include a reflecting mirror. The base frame 120 is formed by, for example, aluminum die casting.

Although hidden in the fitting frame 128 of the base frame 120 in FIG. 2, the light emitting element 190 fixed to the fitting frame 128 is, for example, a laser diode and emits the detection light L1. The detection light L1 emitted from the light emitting element 190 is adjusted by the light projection lens 150 into parallel light or specified spot light, and is projected toward the work W through the light projection window 113 described above. The structure of projection lens holder 160 that holds projection lens 150 and the fixing of projection lens holder 160 to base frame 120 will be described in detail later.

When the detection light L1 is reflected by the work W, it returns to the distance measuring sensor 100 as the detection light L2 along an optical path corresponding to the distance of the work W. FIG. After passing through the light receiving window 114, the detection light L2 is condensed by the light receiving lens 130, reflected by the reflecting mirror 170, and reaches the light receiving sensor 180. FIG. The light-receiving sensor 180 is, for example, a CMOS sensor having a plurality of pixels, and outputs an electrical signal corresponding to the pixel reached by the detection light L2. In this embodiment, the reflecting mirror 170 is adhesively fixed to the housing frame 129 of the base frame 120 , and the light receiving sensor 180 is supported by the base frame 120 via the sensor holder 181 .

3 is a perspective view of the base frame 120. FIG. The base frame 120 generally has a structure in which a plurality of structures each having a function are erected on a plate-like bottom surface 121 . The base frame 120 in this embodiment is integrally molded by aluminum die casting, but the material may be resin or other metal, and a part of the structure is separately formed and fixed. It may be a structure.

The bottom surface 121 is mainly divided into a light-receiving-side bottom surface 121a on which a structure for supporting light-receiving components is erected, and a light-projecting-side bottom surface 121b on which a structure for supporting light-projecting components is erected. classified. The light-receiving-side bottom surface 121a and the light-projecting-side bottom surface 121b are formed as substantially flat portions, but they may be provided with light shielding lines to prevent stray light, or may be lightened.

The light-receiving-side bottom surface 121 a has two protrusions 122 for supporting the light-receiving lens holder 140 in addition to the housing frame 129 described above. Each protruding portion 122 has a substantially quadrangular prism shape that protrudes upward (in the negative direction of the y-axis in the drawing) from the light-receiving side bottom surface 121a (parallel to the xz plane in the drawing). Each upper surface portion 122a is provided with a recess 123, which is a recess for storing adhesive. Further, a part of the wall portion forming the recess 123 in the upper surface portion 122a has a guide groove for allowing the overflowing adhesive to flow out in a specific direction when a large amount of adhesive flows into the recess 123 by the operator. 124 are provided.

In the present embodiment, the recesses 123 are provided by digging the upper surface portions 122a of the respective raised portions 122 in a bathtub shape. Also, the guide groove 124 is provided in a direction along the optical axis of the light receiving lens 130 . When the adhesive that flows in exceeds the capacity of the recess 123, the overflowing adhesive flows through the guide groove 124 to the light-receiving side bottom surface 121a.

The projection-side bottom surface 121 b has two protrusions 125 for supporting the projection lens holder 160 in addition to the fitting frame 128 described above. Each protruding portion 125 has a substantially quadrangular prism shape that protrudes upward (in the negative direction of the y-axis in the drawing) from the bottom surface 121b on the light emitting side (parallel to the xz plane in the drawing). Each upper surface portion 125a is provided with a recess 126, which is a recess for storing adhesive. A part of the wall forming the concave portion 126 on the upper surface portion 125a has a guide groove for letting the overflowing adhesive flow out in a specific direction when a large amount of adhesive flows into the concave portion 126 by the operator. 127 are provided.

In the present embodiment, the recesses 126 are provided by digging in the upper surface portion 125a of each raised portion 125 in a bathtub shape. Also, the guide groove 127 is provided in a direction along the optical axis of the projection lens 150 . When the adhesive that flows in exceeds the capacity of the recess 126, the overflowing adhesive flows through the guide groove 127 to the light-projecting side bottom surface 121b. The direction in which the guide grooves are provided is not limited to the direction along the optical axis, and may be any direction that prevents the overflowing adhesive from coming into contact with optical components such as the light receiving lens holder 140 .

FIG. 4 is a perspective view of the light receiving lens holder 140 that holds the light receiving lens 130. FIG. The light-receiving lens holder 140 is a frame that surrounds and holds the periphery of the light-receiving lens 130, and is made of resin, for example. The light receiving lens holder 140 mainly has a frame portion 141 , arm portions 142 and protrusions 143 . The frame portion 141 has a function of surrounding and holding the periphery of the light receiving lens 130 , and the light receiving lens 130 is fixed using an adhesive after being positioned on the frame portion 141 . The frame portion 141 does not have to surround the entire circumference of the light receiving lens 130, and in the present embodiment, a portion corresponding to the lower end portion of the light receiving lens 130 is notched.

A pair of arm portions 142 extend from the frame portion 141 in a direction perpendicular to the optical axis of the light receiving lens 130 when the frame portion 141 holds the light receiving lens 130, and in the present embodiment, in a direction parallel to the xz plane. is the beam-like portion of The protruding portion 143 is a hook-shaped portion protruding from the tip of each arm portion 142 in a direction perpendicular to the extending direction of the arm portion 142 (in the present embodiment, the y-axis direction, which is the side of the base member). is.

FIG. 5 is a cross-sectional view showing the state of the light receiving lens holder 140 supported by the base frame 120, and more specifically, a cross-sectional view taken along plane C shown in FIG. As described above, the pair of left and right raised portions 122 are provided so as to protrude from the light receiving side bottom surface 121a, and the concave portions 123 are dug in the respective upper surface portions 122a. In the recess 123 , in this embodiment, a UV curable adhesive 200 that hardens when irradiated with UV light (ultraviolet light) by a UV irradiator 210 is stored. The figure shows a state in which the stored adhesive 200 is cured and the light-receiving lens holder 140 is fixed.

As described above, the pair of arm portions 142 extend from the frame portion 141 to the left and right, and the tip portions of the protruding portions 143 formed so as to be bent are inserted into the recess portions 123 and surrounded by the adhesive 200 . there is The light-receiving lens holder 140 is supported by the base frame 120 by fixing the tip of the projection 143 to the hardened adhesive 200 . Observing the light-receiving lens holder 140 supported by the base frame 120 , the protruding portion 122 protrudes from the light-receiving side bottom surface 121 a toward the projecting portion 143 . It can be said that it protrudes from the tip toward the light receiving side bottom surface 121a.

In the operation of fixing the light receiving lens holder 140 to the base frame 120 , the light receiving lens holder 140 is held suspended by a jig in a state where the tip of the projecting portion 143 is soaked in the adhesive 200 before hardening. Then, the detection light L2, which is the reflected light of the detection light L1 projected for adjustment, is actually received by the light receiving sensor 180, and the operator observes the output of the detection light L2, and displaces the jig while observing the light receiving lens holder. Adjust the position and orientation of 140. After the position and orientation are determined, UV light is emitted from the UV irradiator 210 to cure the adhesive 200 . When the adhesive 200 hardens, the holding by the jig is released.

When fixing the light-receiving lens holder 140 to the base frame 120 through such a work process, first, since the concave portion 123 for storing the adhesive 200 is provided on the upper surface of the protuberant portion 122, the work of inflowing the adhesive 200 by the operator is required. becomes easier. In addition, since the adhesive 200 is stored in the concave portion 123, the adhesive 200 does not spread in the surface direction or drip in the direction of gravity. . It should be noted that such fixing work of the light receiving lens holder 140 may be realized by, for example, a work robot recognizing the output of the light receiving sensor 180 and automatically displacing the jig without intervention of an operator. .

The light-receiving lens holder 140 fixed to the base frame 120 in this way has good application balance of the adhesive 200 , that is, good adhesion symmetry between the two projecting portions 143 . If the adhesive symmetry is good, even if the temperature in the usage environment of the distance measuring sensor 100 changes and the hardened adhesive 200 expands or contracts, it does not press the projecting portion 143 in a biased direction. A change in the optical axis of the lens 130 can be minimized. Also, the tip of the projecting portion 143 inserted into the recess 123 does not contact the recess 123 and only contacts the adhesive 200 . According to such a structure, even if external vibrations or shocks are applied in the usage environment, the adhesive 200 having a lower rigidity than the base frame 120 and the light receiving lens holder 140 absorbs them, thereby allowing the light receiving lens holder to absorb the vibrations and impacts. It can be expected that the displacement of 140 is suppressed.

Further, in this embodiment, the distance h ₂ from the light receiving side bottom surface 121 a to the upper surface portion 122 a is larger than the distance h ₁ from the light receiving side bottom surface 121 a to the lower end of the effective diameter of the light receiving lens 130 . That is, the upper surface portion 122 a is positioned above the lower end of the effective diameter of the light receiving lens 130 held by the light receiving lens holder 140 . By setting the protruding portion 122 higher within such a range, the protruding portion 143 of the light receiving lens holder 140 can be shortened. If the projecting portion 143 can be shortened, the bending of the projecting portion 143 can be suppressed even if the adhesive 200 expands/contracts due to external vibration or impact, and thus displacement of the optical axis of the light receiving lens 130 can be suppressed. .

In addition, in this embodiment, the base frame 120 is entirely subjected to alumite treatment except for at least the concave portion 123 . By subjecting the surface to alumite treatment, light absorbability is obtained, and the stray light of the detection lights L1 and L2 can be effectively absorbed. On the other hand, the surface of the concave portion 123 that stores the UV-curable adhesive 200 contributes to curing of the adhesive 200 if it reflects the UV light well. Therefore, the surface of the concave portion 123 is excluded from the alumite treatment. Note that the difference in treatment between the surface of the recess 123 and the other surface of the base frame 120 is not limited to this method. Even if the UV light reflectance of the concave portion 123 is made higher than that of other surfaces, particularly the surface of the light receiving side bottom surface 121a, by subjecting the surface of the concave portion 123 to a mirror surface treatment such as aluminum vapor deposition. good.

In this embodiment, the light projecting lens holder 160 that holds the light projecting lens 150 is also fixed to the base frame 120 in the same manner as the light receiving lens holder 140 . FIG. 6 is a perspective view of projection lens holder 160 that holds projection lens 150 .

The projection lens holder 160 is a frame that surrounds and holds the periphery of the projection lens 150, and is made of resin, for example. The projection lens holder 160 mainly has a frame portion 161 , an arm portion 162 and a projecting portion 163 . The frame portion 161 has a function of surrounding and holding the periphery of the projection lens 150 , and the projection lens 150 is fixed using an adhesive after being positioned on the frame portion 161 . The frame portion 161 may have a box shape and hold a projection lens group composed of a plurality of projection lenses.

The arm portions 162 extend from the frame portion 161 in a direction orthogonal to the optical axis of the projection lens 150 when the frame portion 161 holds the projection lens 150, and in a direction parallel to the xz plane in this embodiment. It is a pair of beam-shaped parts. The protruding portion 163 is a hook-shaped portion protruding from the tip of each arm portion 162 in a direction perpendicular to the extending direction of the arm portion 162 (the y-axis direction, which is the side of the base member in this embodiment). is.

The light projecting lens holder 160 has an arm portion 162 with a wider width w along the optical axis direction than the light receiving lens holder 140 . Specifically, the width w is larger than the height h, which is the projection length of the projecting portion 163 from the arm portion 162 . If the arm extends in a direction orthogonal to the optical axis of the lens, vibrations and shocks tend to tilt the surface of the lens. If it is formed relatively long along the optical axis direction, it will be resistant to surface tilt.

A through hole 164 is provided at the boundary between the arm portion 162 and the projecting portion 163 . The through-hole 164 allows the irradiated UV light to pass through when the tip of the protruding portion 163 is inserted into the adhesive 200 stored in the concave portion 126 of the protruding portion 125, thereby allowing more UV light to pass to the adhesive 200. It has the function of guiding. Therefore, it can be expected that the adhesive 200 hardens more quickly than when the through holes 164 are not provided.

The projecting lens holder 160 configured in this manner can also be fixed to the base frame 120 in the same manner as the method of fixing the receiving lens holder 140 described with reference to FIG. In the case of the projection lens holder 160, the tip of the projecting portion 163 is immersed in the uncured adhesive 200 and is held suspended by a jig. The operator adjusts the position and orientation of the projection lens holder 160 by displacing the jig while observing .

Although the distance measuring sensor 100 according to this embodiment has been described above, one of the light receiving lens holder 140 and the light projecting lens holder 160 may be fixed to the base frame 120 by another method. Further, for example, although it has been described that the projecting portion 143 of the light receiving lens holder 140 projects in a direction orthogonal to the arm portion 142, any shape in which the tip of the projecting portion is inserted into the adhesive stored in the recess may be used. For example, the relationship between the arm portion and the projecting portion is not limited to this. For example, it may have a curved beam shape that is continuously formed from the arm portion to the projecting portion.

Further, in the present embodiment described above, the pair of arms 142 extends in the direction orthogonal to the optical axis of the light receiving lens 130, but the direction in which the arms extend does not correspond to the optical axis of the held lens. Similar effects can be expected as long as they are not parallel to the lens optical axis, even if they are not perpendicular to . For example, a pair of arms may be V-shaped or inverted V-shaped, each extending in a direction 60 degrees with respect to the optical axis. Moreover, the structure may be such that the arm extending in one direction is bifurcated.

[Appendix]
a lens (130, 150);
a frame (140, 160) holding the lens;
A base member (120) that supports the frame,
The frame is
a pair of arms (142, 162) extending in a direction not parallel to the optical axis of the held lens;
a projecting portion (143, 163) provided projecting from the tip of the arm toward the base member,
The base member is
a flat portion (121);
and protruding portions (122, 125) protruding from the flat portion to the side of the protruding portion and provided with recesses (123, 126) for storing the adhesive (200) on the upper surface portions (122a, 125a). ,
A lens support structure (100) in which the frame is supported by the base member by inserting the tip of the protrusion into the recess and surrounding it with the adhesive.

DESCRIPTION OF SYMBOLS 100... Ranging sensor, 111... Housing, 112... Cable, 113... Emitter window, 114... Light-receiving window, 120... Base frame, 121... Bottom surface, 121a... Bottom surface on light receiving side, 121b... Bottom surface on light emitting side, 122... Protrusion 122a Upper surface 123 Recess 124 Guide groove 125 Protrusion 125a Upper surface 126 Recess 127 Guide groove 128 Fitting frame 129 Accommodating frame 130 Light receiving Lens 140 Light receiving lens holder 141 Frame 142 Arm 143 Projection 150 Projection lens 160 Projection lens holder 161 Frame 162 Arm 163 Projection , 164... Through hole 170... Reflecting mirror 180... Light receiving sensor 181... Sensor holder 190... Light emitting element 200... Adhesive 210... UV irradiator

Claims (7)

a lens;
a frame that holds the lens;
A base member that supports the frame,
The frame is
a pair of arms extending in a direction not parallel to the optical axis of the held lens;
a projecting portion provided to project from the tip of the arm toward the base member;
The base member is
a flat portion;
a protruding portion that protrudes from the flat portion toward the protruding portion and has a recess that stores an adhesive on the upper surface thereof;
A lens support structure in which the frame is supported by the base member by inserting the tip of the protrusion into the recess and surrounding it with the adhesive. 2. The lens support structure according to claim 1, wherein the upper surface portion is located above the lower end of the lens held by the frame. 3. The lens support structure according to claim 1, wherein a part of the wall forming the recess is provided with a groove for flowing out the adhesive overflowing from the recess. 4. The lens support structure according to any one of claims 1 to 3, wherein the protruding portion has a parallel length parallel to the optical axis direction of the lens longer than a protruding length from the arm toward the base member. body. 5. The lens support structure according to any one of claims 1 to 4, wherein a through hole is provided in a boundary portion between the arm portion and the projecting portion. The adhesive includes at least an ultraviolet curable adhesive,
6. The lens support structure according to any one of claims 1 to 5, wherein a surface treatment is applied so that the ultraviolet reflectance of the surface of the recess is higher than the ultraviolet reflectance of the surface of the flat portion. The lens support structure according to any one of claims 1 to 6 is provided between a light emitting element and a light projecting window, and between a light receiving window and a light receiving sensor. An optical distance measuring sensor employed as a structure that supports at least one of light receiving lenses.

Images